Clinical Observation of Immunotherapy Combined with CT-Guided Stereotactic Ablation Brachytherapy for Early-Stage Unresectable Non-Small Cell Lung Cancer

Background: To observe the safety and efficacy of immunotherapy combined with CT-guided stereotactic ablation brachytherapy(I-SABT) in early-stage unresectable non-small cell lung cancer (NSCLC). Methods: Collect early-stage unresectable non-small cell lung cancer patients who received I-SART in our hospital from January 2019 to December 2023. Evaluated the safety and efficacy of treatment, and analyzed their prognostic factors. Results: A total of 23 patients with early-stage non-small cell lung cancer (T1-3N0M0 stage Ia-IIb) were included, including 17 cases of squamous cell carcinoma and 6 cases of adenocarcinoma (all driver genes tested negative); There were 14 smokers and 9 non-smokers, all patients were deemed ineligible for surgery or declined standard radiotherapy or chemoradiotherapy. The median follow-up time was 36.5 months (range: 17.2 - 77.5). The median event free survival (mEFS) was 49.2 months, and DCR at 1, 3, and 4 years were 100.0% (23/23), 91.3% (21/23), and 82.6% (19/23), respectively. Procedure-related adverse events were predominantly Grade I-II: pneumothorax (10/23, 43.5%), hemorrhage (3/23, 13.0%), and pain (1/23, 4.3%). Pneumothorax incidence was significantly associated with patient positioning and number of needle passes. Lateral decubitus positioning resulted in a higher pneumothorax rate (83.3%, 5/6) compared to supine/prone positioning (29.4%, 5/17; P = 0.022). >9 needle passes led to a higher pneumothorax rate (66.7%, 8/12) versus ≤9 passes (18.2%, 2/11; P = 0.019). Immune-related adverse events were limited to Grade I-II: fatigue (6/23, 26.1%), hypothyroidism (2/23, 8.6%), and immune-mediated pneumonitis (3/23, 13.0%). Univariate analysis showed that ECOG 0 - 1, smoking, left lung disease, GTV D90 ≥ 140 Gy and PD-L1 expression ≥ 1% had better mEFS (p Conclusions: I-SABT can improve the survival benefits of patients with early-stage unresectable non-small cell lung cancer, and demonstrates a favorable safety profile. GTV D90 ≥ 140 Gy and PD-L1 expression ≥ 1% were associated with improved clinical outcomes. Patients receiving I-SABT exhibited superior prognosis compared to conventional therapies.